023 require computed in pipeline

// TEST: kernel:init in a pipeline REQUIRES | computed — twin of 390_054 at depth.
//
// NEGATIVE test (expected_error.txt pins the rejection). The rule is
// position-blind: a kernel whose result is never observed is dead
// computation at any depth. This test was green pre-a24afd06 only because
// the old nested path enforced the rule against the containing flow — an
// accident of the top-level/nested duality, not a sanctioned form.
// Placement-legality of nested init (WITH computed) is carried by 390_091.

~import std/kernel
~import std/io

~std/kernel:shape(Body) {
    mass: f64,
}

~event get-count {}
| n u32

~proc get-count|zig {
    return .{ .n = 3 };
}

~get-count()
| n _ |> std/kernel:init(Body) {
        { mass: 1.0 },
        { mass: 2.0 },
        { mass: 3.0 },
    }
    | kernel k |> std/kernel:pairwise { k.mass += k.other.mass }

~std/io:print.ln("done")